Simvastatin increases temozolomide-induced cell death by targeting the fusion of autophagosomes and lysosomes.

Abstract

Temozolomide (TMZ) is a chemotherapy agent used to treat Grade IV astrocytoma, also known as glioblastoma (GBM). TMZ treatment causes DNA damage that results in tumor cell apoptosis and increases the survival rate of GBM patients. However, chemoresistance as a result of TMZ-induced autophagy significantly reduces this anticancer effects over time. Statins are competitive inhibitors of HMG-CoA reductase, the rate-limiting enzyme of the mevalonate (MEV) cascade. Statins are best known for their cholesterol (CH)-lowering effect. Long-term consumption of statins, prior to and in parallel with other cancer therapeutic approaches, has been reported to increase the survival rate of patients with various forms of cancers. In this study, we investigated the potentiation of TMZ-induced apoptosis by simvastatin (Simva) in human GBM cell lines and patient GBM cells, using cell monolayers and three-dimensional cell culture systems. The incubation of cells with a combination of Simva and TMZ resulted in a significant increase in apoptotic cells compared to cells treated with TMZ alone. Incubation of cells with CH or MEV cascade intermediates failed to compensate the decrease in cell viability induced by the combined Simva and TMZ treatment. Simva treatment inhibited the autophagy flux induced by TMZ by blocking autophago-lysosome formation. Our results suggest that Simva sensitizes GBM cells to TMZ-induced cell death in a MEV cascade-independent manner and identifies the inhibition of autophagosome-lysosome fusion as a promising therapeutic strategy in the treatment of GBM.

• Authors: Shahla Shojaei, Navid Koleini, Ehsan Samiei, Mahmoud Aghaei, Laura K Cole, Javad Alizadeh, Md Imamul Islam, Amir-Reza Vosoughi, Mohammed Albokashy, Yaron Butterfield, Hassan Marzban, Fred Xu, James Thliveris, Elissavet Kardami, Grant M Hatch, Eftekhar Eftekharpour, Mohsen Akbari, Sabine Hombach-Klonisch, Thomas Klonisch, Saeid Ghavami
• Journal: The FEBS journal (FEBS J) Vol. 287 Issue 5 Pg. 1005-1034 (03 2020) ISSN: 1742-4658 [Electronic] England
• PMID: 31545550 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2019 Federation of European Biochemical Societies.

Chemical References

• Macrolides
• bafilomycin A1
• Simvastatin
• Temozolomide

Topics

• Animals
• Autophagosomes (drug effects, metabolism)
• Cell Death (drug effects)
• Cell Line, Tumor
• Female
• Glioblastoma (metabolism)
• Humans
• Lysosomes (drug effects, metabolism)
• Macrolides (pharmacology)
• Mice
• Simvastatin (pharmacology)
• Temozolomide (pharmacology)
• Xenograft Model Antitumor Assays